Reform Judaism only trickles through Europe and Israel now, but Rabbi Richard Block of Congregation Beth Am in Los Altos Hills wants to see the liberal movement flow like a mighty river.

Chosen as the new executive director of the World Union for Progressive Judaism, Block will steer the agency straight into the pitched battles over the Orthodox monopoly on religion in Israel. He succeeds Rabbi Richard Hirsch, who is retiring after holding the position for 25 years.

"The next 20 years will determine the course of the progressive Jewish movement in the world," said Block, who will remain at Beth Am through June. "Part of my job is to be a strong advocate in political and religious circles to bring about the realization of Israel as a home for all Jews."

He does not officially begin his position until July. But Block is already having an impact on the Jerusalem-based umbrella agency for the approximately 2 million Jews worldwide in the Reform and Reconstructionist movements.

Last month Block went globe-trotting for WUJP, visiting France, Germany and Israel to investigate issues facing liberal Jews there.

European rabbis stressed a need for more progressive institutions and rabbis to serve growing populations of mostly unaffiliated Jews. Block said the Reform movement's Hebrew Union College-Jewish Institute of Religion is trying to set up a rabbinical school in Moscow, as well as entice non-native rabbis to take posts in Europe's congregations.

"We have the opportunity in the former Soviet Union to become the dominant orientation," he said.

In Jerusalem, Block said he'll petition for funds and land to erect more schools and synagogues for Israel's liberal movements. Reform Jews there have only a handful of rabbis and permanent buildings despite polls indicating a substantial interest in non-Orthodox Judaism.

"We have a window of opportunity because we are in the midst of a renaissance in spirituality," he said. Reform leaders literally need to "build a movement [to meet] the tremendous upsurge of interest among Israelis who are calling for a religious alternative."

Block has made his mark at Beth Am with avant-garde programming. In his 12 years as the congregation's senior rabbi, Block has designed a nationally acclaimed program to reach out to former Soviet Union emigres, pairing emigre families with American families with emphasis on bringing children to synagogue. The congregation features regular trilingual Shabbat services and a monthly newsletter in Russian.

Block has also put Beth Am at the forefront of education by hiring two rabbis to focus almost exclusively on finding creative ways to teach congregants.

"I have loved my years at Beth Am. It has been a privilege and a joy," he said. "I wouldn't be leaving what I feel is the best job in the congregational rabbinate unless I was profoundly optimistic" about the new mission.

Block, who is married with two sons, also served as president of Northern California and Pacific Northwest region of the Association of Reform Zionists of America.

A self-described born and bred Reform Jew, Block trumpets the movement as a mix of "tradition and modernity, promoting egalitarianism and committed to social justice."

Now, as leader of the world movement of liberal Judaism, he'll put those beliefs into action by fighting for official recognition from the Israeli government. But Reform acceptance, he said, does not need to come at the expense of sacrificing Orthodox values.

"There are plenty of Jews to go around," Block said. "We don't have any conflict with Orthodox Jews; we're not out to harm them or even compete with them."

In any country other than Israel, he said, Orthodox-only religious laws "would be a form of religious oppression." But a coalition with moderate Orthodox Jews is not out of the question.

Though Israelis have expressed frustration at "corruption and politicization by the ultra-Orthodox," many may not be aware progressive Judaism has a spiritual tradition to meet their needs, Block said.

"I want to make progressive Judaism truly an indigenous identity in Israel. Right now it seems to be almost a secret. Hopefully we can take it to a fully vibrant and substantial movement."